My daughter and son-in-law bought a house with a fiberglass pool. It keeps having foam on the top of the water. The pool is 10.5' x 20' and 4' deep. We have checked the chlorine, alkalinity, and ph. The ph was a little low, so we added some ph plus to bring it up. We also put clarifier in it. What else could be causing the foam? They can't seem to get anyone from any of the local pool places to come to their house, and I have done everything I know to do.

Many commercial algecides will foam when used in the pool. Go to the local pool supply house and ask for a de-foamer. I believe that it comes in quart bottles. After that, try buying a "no foam" algicide and use that in the future.